By Chris Woolston, M.S.
In an ideal world, you'd never have to worry about your food becoming contaminated by animal waste. But unfortunately, conditions in factories and on farms can be less than sanitary, and we all have to live with the consequences -- including the threat of salmonella bacteria. These germs, found in the intestines of infected humans and animals (and spread through the fecal matter of many animals), possibly sicken more than 1.2 million Americans each year, making salmonella one of the leading causes of food poisoning in this country.
Why is the disease called salmonella? Does it have anything to do with the fish?
No, salmonella is named for the American veterinarian Dr. Daniel E. Salmon, who first identified that strain of bacteria.
What are the symptoms of salmonella poisoning?
If enough salmonella germs get into your stomach, your body will work hard to get rid of them. Within 12 to 72 hours, you'll have diarrhea along with stomach cramps and a fever. The symptoms usually fade after five to seven days, although it may take several months to get completely back to normal.
Most people recover fully from salmonella infections. In rare cases, the germs can spread from the intestines to other parts of the body, causing long-term joint pain and other complications. According to the Centers for Disease Control and Prevention, about 450 Americans die from salmonella poisoning each year. Infants, the elderly, and people with weakened immune systems are especially likely to become seriously ill if they catch salmonella.
How does salmonella spread?
Salmonella is commonly found on the surface of all sorts of meat, including beef and poultry. Consumer Reports found the germ in 15 percent of broiler chickens purchased at grocery stores across the country. Interestingly, salmonella was especially common in chickens labeled "organic." In fact, there is no evidence that organic, Kosher, or chickens labeled "natural" have any less salmonella bacteria than other poultry, according to the government's Food Safety and Inspection Service.
The bacteria also thrive in fish, eggs, unpasteurized milk, and fruits and vegetables. Somewhat surprisingly, the frozen food aisle can be another danger zone. In 2007, at least 272 people in 35 states fell sick with an identical strain of salmonella that evidently came from frozen pot pies.
Food poisoning is by far the main source of salmonella infections. But it's also possible to contract the illness after handling chickens and ducks or lizards, turtles, and other reptiles, all of which are more likely to carry salmonella.
How can I prevent salmonella poisoning?
The most important thing you can do to prevent salmonella poisoning is to avoid eating risky foods, including unpasteurized milk and undercooked chicken, meat, and eggs. Fortunately, thoroughly cooking them will kill salmonella. Chicken and ground beef should be cooked until all traces of pink disappear. (Eating ground beef is riskier than steak because germs can be mixed throughout the meat, not just present on the surface.) You should also be careful when preparing these foods in the kitchen. For your family's safety, wash your hands thoroughly with soap and warm water after handling such foods, and give cutting boards, countertops, and utensils the same treatment. To prevent salmonella from spreading to salad fixings, use separate cutting boards for meats and vegetables.
Don't eat products made with raw eggs, including homemade cookie dough. (Store-bought cookie dough is often pasteurized, but check the label to be sure. Since salmonella is especially hard on young bodies, resist the temptation to let young children lick the spoon when making cake or cookies.
Although there have been a few cases of salmonella outbreaks at sushi restaurants, sushi doesn't appear to be more likely to spread the illness. If you're preparing fish at home, it still makes sense to make sure that the surface is cooked, and clean up any raw juices.
If you have a pet reptile, make sure everyone in the house washes their hands thoroughly after handling it. Ditto for backyard chickens. Elderly people, very young children, and people with weak immune systems should not touch the animals at all.
How is salmonella diagnosed?
A diagnosis of salmonella is based on the results of lab tests done on a stool sample from an infected person. However, many kinds of illnesses can cause diarrhea, fever, or abdominal cramps, so the lab may not screen for salmonella bacteria unless specifically instructed to look for the germ.
How is salmonella poisoning treated?
The vast majority of cases of salmonella poisoning don't require any treatment. You can take care of yourself by drinking plenty of fluids until the diarrhea stops. If you become severely dehydrated, you may need to go to the hospital to receive intravenous fluids. Persistent infections or those that spread beyond the digestive system will need to be treated with antibiotics. (However, Reiter's syndrome, a complication of salmonella poisoning, does not respond to antibiotics.)
But with salmonella and other types of food poisoning, prevention is still the best treatment of all.
Food and Drug Administration. Focus on: Salmomella poisoning.
Centers for Disease Control and Prevention. Investigation of outbreak of human infections caused by Salmonella.
Consumer Reports. Chicken Safety: Dangerous bacteria, contamination.
Centers for Disease Control and Prevention. Salmonellosis.
Heinitz ML et al. Incidence of Salmonella in fish and seafood. Journal of Food Protection. 2000. 63: 579-592.
USDA Fact Sheet: Foodborne Illness and Disease Salmonella Questions and Answers.
American Museum of Veterinary Medicine. Noteworthy Veterinarians Daniel E. Salmon, DVM.
Food and Drug Administration. Food Safety for Moms-to-Be. Safe Eats.
Food and Drug Administration. FDA tips to prevent foodborne illness this holiday season.